[johnnyb]

Just getting around to cleaning some corny kegs a friend gave me, and I have one with a brownish stain in the bottom that I can't remove. It is probably a spot where a bit of liquid (assuming beer because he was a brewer but who knows) pooled for a long period of time. It's not a solid brown spot. It's more like sort of haphazard rings of various shades of brown and roughly 3" across.

So far I've tried PBW, Craft Meister Alkaline Brewery Wash, and StarSan with no luck.

I just want to use this keg for periodic cleaning of beer lines, so I'm not sure if the stain is a big deal. But I would feel better if I could get it cleaned up.

Any ideas? 

[narcout]

Bar Keeper's Friend

[Philbrew]

Might be rust.  Passivate the SS with a couple cups of muriatic acid.

[Wort-H.O.G.]

Might be rust.  Passivate the SS with a couple cups of muriatic acid.

my bet its in a blemish in the glass....from production. i have one with the same thing...brownish spot on bottom and its clearly in the layer of glass.

throw crap ton of oxyclean in there..if it doesn't come out its likely in the glass.

[hopfenundmalz]

Might be rust.  Passivate the SS with a couple cups of muriatic acid.

my bet its in a blemish in the glass....from production. i have one with the same thing...brownish spot on bottom and its clearly in the layer of glass.

throw crap ton of oxyclean in there..if it doesn't come out its likely in the glass.

Glass in a corny keg???

[Wort-H.O.G.]

Might be rust.  Passivate the SS with a couple cups of muriatic acid.

my bet its in a blemish in the glass....from production. i have one with the same thing...brownish spot on bottom and its clearly in the layer of glass.

throw crap ton of oxyclean in there..if it doesn't come out its likely in the glass.

Glass in a corny keg???

haha my bad. i could have sworn i read carboy....only had one beer so far 

[hopfenundmalz]

Might be rust.  Passivate the SS with a couple cups of muriatic acid.

Isn't Nitric acid used to passivate SS in industrial settings, as it is an oxidizer.

[johnnyb]

I guess it could be rust, but it sure doesn't look like rust. I can't imagine what else it could be though that wouldn't have come off with the cleaners that I've tried.

Can I use phosphoric acid? And if yes, how much should I dilute it?

[hopfenundmalz]

Here is advice from a metallurgist named Palmer. Bar Keepers Friend is the source of oxalic acid. You might need someone with skinny arms to reach the bottom to scrub.
http://www.howtobrew.com/appendices/appendixB-1.html

[johnnyb]

Thanks.

[Slowbrew]

Here is advice from a metallurgist named Palmer. Bar Keepers Friend is the source of oxalic acid. You might need someone with skinny arms to reach the bottom to scrub.
http://www.howtobrew.com/appendices/appendixB-1.html

One of those sponge on one side and scrubby pad on the other and a broom handle can work in place of the skinny arm too.

Paul

[zorch]

Here is advice from a metallurgist named Palmer. Bar Keepers Friend is the source of oxalic acid. You might need someone with skinny arms to reach the bottom to scrub.
http://www.howtobrew.com/appendices/appendixB-1.html

I keep a toilet bowl brush (never used on a toilet, of course) for keg scrubbing duties.

[brewinhard]

You might need someone with skinny arms to reach the bottom to scrub.

Ha!  I know exactly what you are talking about.  Got my arm caught in one a few weeks back.  Next time I will hold my wife upside down by her legs and let her go in for a good cleaning. 

[Stevie]

My arms are just long and skinny enough to get shoulder deep into a keg allowing me to rest my palm flat on the bottom. Makes my yearly deep clean and rebuild easier.

[reverseapachemaster]

You might need someone with skinny arms to reach the bottom to scrub.

Ha!  I know exactly what you are talking about.  Got my arm caught in one a few weeks back.  Next time I will hold my wife upside down by her legs and let her go in for a good cleaning.

Words to live by.